1. Field of the Invention
This application relates to an automatic color bobbin changer and has as its objective the provision of a new and improved apparatus of this general class.
An important purpose of the present invention is to provide an automatic color bobbin changer device that can be easily secured to a conventional sewing machine without making any change in the sewing machine. In particular, the adaptation of the present invention to a sewing machine can be completed in 15 minutes or less. It is contemplated that the device of the present invention can also be secured to automated sewing machines.
Under present practice, bobbins or bobbin cases are removed by the operator in a series of finger manipulations. The bobbin case is provided with a spring loaded latch and one of the advantages of the present invention is that it is effective with bobbin cases as presently constituted without requiring that a bobbin case of special construction be provided in order to remove the bobbin case manually. The spring loaded latch is raised in manual procedures by action of an index finger with the thumb acting as a backup. Once the latch is raised, the thumb of the forefinger grip the latch and pull the bobbin out.
The foregoing is a time consuming and tedious effort which is not only eliminated by the present invention, but the device of the present invention performs the operation of removing the old bobbin case and inserting a bobbin case of desired color thread in 2 to 4 seconds. The manual operation normally takes 30 seconds and is quite tedious as well as annoying to the operator who has to stop work in order to make the change. There is also the possibility of operator error in color selection, particularly with partially used bobbins.
Moreover, the device of the present invention may be coupled together with the automatic thread changer of U.S. Pat. Nos. 4,036,157 and 4,075,958.
2. Description of the Prior Art
Prior automatic devices have not had the advantages of the present invention. The devices of Schumann U.S. Pat. Nos. 2,690,725 and 2,733,676 require the use of a specially constructed bobbin case wherein the latch hinge has been completely removed from the bobbin case. Moreover, the Schumann devices cannot change colors and are effective only in removing and discarding an empty bobbin as compared with the present invention that is operative with both the empty bobbin as well as a partly full bobbin. With the Schumann devices, a completely empty or a partly used bobbin is ejected from the sewing machine by hook-type means. Schumann fails to show an apparatus which is capable of automatically reintroducing a partly used bobbin to the sewing machine at a later time when needed.
In the bobbin changing device of U.S. Pat. No. 3,747,547 it is necessary to provide a bobbin of special design and such device is not operative with a conventional bobbin.
Accordingly, it is an object of the present invention to provide an automatic color bobbin changer which is operative with a conventional bobbin to achieve the changing of an empty or partly full bobbin at an extremely fast rate of speed.
Yet another object of the present invention is to provide an automatic color bobbin changer which can remove from the sewing machine a partly full bobbin and later re-insert such partly full bobbin in the sewing machine when needed.